Car is an 03 GT with the 3400, it was throwing an intermediate p0101 code so I changed the maf also threw in a new air filter. now I have p0101 and p0102, when i drive it around town I can't get the lights to come back after I reset them and the car drives perfect. However she drove the car maybe 20 miles a little more and she explains that it dies when slowing down, either backfire or misses and smells like rotten eggs. Getting about 23 mpgs. I inspected the ground and for the MAF circuit and it visually looked fine. I'm curious if I might be dealing with a clogged cat. Thoughts?? Thanks